How do I get last modified date of website - asp.net

Question

I have website URL's in a DataGridView Cell when I click on the Cell the website is loaded in Chrome. I am using VS 2019 and VB.Net only I do not have ASP.Net installed.
I have tried a bunch of different concepts from some SO post that go back to 2011
With very little success I found one function that looked workable but no results I will post that code.
My question is How do I get last modified date of website?
If using VB.Net ONLY is not workable point me to a reference for other tools needed.
Public Property DateTime_LastModified As String
Dim webPAGE As String
This code is inside a click event for the DataGridView
ElseIf gvTxType = "View" Then
webPAGE = row.Cells(2).Value.ToString()
'Modified: <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
Process.Start(webPAGE)
GetDateTimeLastModified(requestUriString)
Label1.Text = DateTime_LastModified
'Dim strPath As String = webPAGE + "javascript : alert(document.lastModified)"
'Dim strPath As String = Request.PhysicalPath
'Server.MapPath
'Label1.Text = System.IO.File.GetLastWriteTime(webPAGE).ToString()
'Label1.Text = strPath '"Modified: " + System.Web.UI.GetLastWriteTime(strPath).ToString()
'Label1.Text = strPath + "Modified:" + System.MapPath.Request.ServerVariables.Get("SCRIPT_NAME")
'Process.Start(webPAGE)
Here is the Edit I tried from the Answer
Public Class GetURLdate1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim strURL As String
strURL = TextBox1.Text
Dim client = New HttpClient()
Dim msg As New HttpRequestMessage(HttpMethod.Head, strURL)
Dim resp = client.SendAsync(msg).Result
Dim strLastMod As String = resp.Content.Headers.LastModified.ToString
MsgBox("Last mod as string date" & vbCrLf & strLastMod)
'Dim lastMod As DateTime = CDate(strLastMod)
'MsgBox(lastMod)
End Sub
Private Sub GetURLdate1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
TextBox1.Text = "https://www.youtube.com/c/stevinmarin/videos"
'"https://stackoverflow.com/questions/70825821/how-do-i-get-last-modified-date-of-website"
End Sub
Returns NO Value for strLastMod

Answer 1

Ok, so it not clear if you need a routine to go get all the URL's in the grid, and update the last updated for each site/url?
Or are you looking to ONLY update the site WHEN you click on the button to jump to the site?
It is easy to do both.
I mean, say we have this markup - drop in a gridview (I let the wizards created it).
I then blow out the datasoruce control, and then remove the data soruce ID setting from the GV
So, I have this markup:
<div style="padding:35px">
<asp:GridView ID="GridView1" runat="server" CssClass="table" Width="65%"
AutoGenerateColumns="False" DataKeyNames="ID" >
<Columns>
<asp:BoundField DataField="Url" HeaderText="Url" ItemStyle-Width="500" />
<asp:BoundField DataField="LastUpDated" HeaderText="Last UpDated" />
<asp:BoundField DataField="LastVisit" HeaderText="Last Visit" />
<asp:TemplateField HeaderText="View" ItemStyle-HorizontalAlign="Center" >
<ItemTemplate>
<asp:Button ID="cmdJump" runat="server" Text="View" CssClass="btn"
OnClick="cmdJump_Click"
/>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
<br />
<asp:Button ID="cmdGetAll" runat="server" Text="Upate all Last updated" CssClass="btn" />
</div>
Ok, and my code to load the gv is this:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
LoadGrid()
End If
End Sub
Sub LoadGrid()
Using conn = New SqlConnection(My.Settings.TEST4)
Using cmdSQL = New SqlCommand("SELECT * FROM tblSites", conn)
Dim rstData As New DataTable
conn.Open()
rstData.Load(cmdSQL.ExecuteReader)
GridView1.DataSource = rstData
GridView1.DataBind()
End Using
End Using
End Sub
And now we have this:
Ok, so just dropped in a plane jane button into the GV. When I click on that button, I will update the last visit - not clear if you ALSO want this to update the last update for the given url?
we can do both.
So, out simple button we dropped? Well, lets have it update the last time we visit (click) to jump to the site).
Protected Sub cmdJump_Click(sender As Object, e As EventArgs)
Dim cmdView As Button = sender
Dim gRow As GridViewRow = cmdView.NamingContainer
Dim PKID As Integer = GridView1.DataKeys(gRow.RowIndex).Item("ID")
' udpate with last visit click
Using conn = New SqlConnection(My.Settings.TEST4)
Using cmdSQL = New SqlCommand("update tblSites SET LastVisit = #Visit WHERE ID = #ID", conn)
conn.Open()
cmdSQL.Parameters.Add("#Visit", SqlDbType.DateTime).Value = Date.Now
cmdSQL.Parameters.Add("#ID", SqlDbType.Int).Value = PKID
cmdSQL.ExecuteNonQuery()
End Using
End Using
' Now jump to that url
Response.Redirect(gRow.Cells(0).Text)
End Sub
And the button to go fetch and update all last updates (every row) of the given URL's cna be this:
Protected Sub cmdGetAll_Click(sender As Object, e As EventArgs) Handles cmdGetAll.Click
Using conn = New SqlConnection(My.Settings.TEST4)
Using cmdSQL = New SqlCommand("SELECT * FROM tblSites", conn)
Dim rstData As New DataTable
conn.Open()
rstData.Load(cmdSQL.ExecuteReader)
For Each OneRow As DataRow In rstData.Rows
Dim client = New HttpClient()
Dim msg As New HttpRequestMessage(HttpMethod.Head, OneRow("Url").ToString)
Dim resp = client.SendAsync(msg).Result
Dim lastMod As DateTimeOffset? = resp.Content.Headers.LastModified
OneRow("LastUpDated") = lastMod.Value.ToString
Next
Dim da As New SqlDataAdapter(cmdSQL)
Dim daU As New SqlCommandBuilder(da)
da.Update(rstData)
' now re-load grid
LoadGrid()
End Using
End Using
End Sub
So, the above has the code to update the data for all URL's.
But, your question seems to suggest that when you click on the GV row button, you ALSO want to get/save/update the given row of the GV with the last update information from the web site url?
Ok, then, we modify our click code, to update both our last click visit, and then also get that web site last update information.
So, just change the button click row code to this then:
Protected Sub cmdJump_Click(sender As Object, e As EventArgs)
Dim cmdView As Button = sender
Dim gRow As GridViewRow = cmdView.NamingContainer
Dim PKID As Integer = GridView1.DataKeys(gRow.RowIndex).Item("ID")
Dim client = New HttpClient()
Dim msg As New HttpRequestMessage(HttpMethod.Head, gRow.Cells(0).Text)
Dim resp = client.SendAsync(msg).Result
Dim lastMod As DateTime = resp.Content.Headers.LastModified.ToString
' udpate with last visit click, and also get laste update from web site
Using conn = New SqlConnection(My.Settings.TEST4)
Dim strSQL As String =
"update tblSites SET LastVisit = #Visit,LastUpdated = #LastUpDate WHERE ID = #ID"
Using cmdSQL = New SqlCommand(strSQL, conn)
conn.Open()
cmdSQL.Parameters.Add("#Visit", SqlDbType.DateTime).Value = Date.Now
cmdSQL.Parameters.Add("#LastUpDate", SqlDbType.DateTime).Value = lastMod
cmdSQL.Parameters.Add("#ID", SqlDbType.Int).Value = PKID
cmdSQL.ExecuteNonQuery()
End Using
End Using
' Now jump to that url
Response.Redirect(gRow.Cells(0).Text)
End Sub
Edit: Not using asp.net
I now see in your post that you suggest you are not using asp.net. However, the above code would work near the same if you are say using a vb.net desktop + gridview. In other words, the code should be similar, and that includes the code to get that web site date.
so, you need to use follow hyper link, but the code to get the date from the web site, and even your general form layout for desktop. The results - even the way your gird looks will thus be very similar to the above web page, the overall idea here thus applies equal well to desktop or web based. I mean, if you have visual studio installed, then you could try above - as VS does install the web bits and parts for you.
Edit #2 - code to get last modified date.
There is NOT some process start, NEVER suggested to use as such. The code you need is thus this:
webPAGE = row.Cells(2).Value.ToString()
Dim client = New HttpClient()
Dim msg As New HttpRequestMessage(HttpMethod.Head,webPAGE)
Dim resp = client.SendAsync(msg).Result
Dim lastMod As DateTime = resp.Content.Headers.LastModified.ToString
MsgBox("DATE " & lastMod)
Edit#3: Code as win forms
Ok, so we create a blank new windows form.
Drop in a text box, drop in a button.
We have this code:
Imports System.Net.Http
Public Class GetURLdate1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim strURL As String
strURL = TextBox1.Text
Dim client = New HttpClient()
Dim msg As New HttpRequestMessage(HttpMethod.Head, strURL)
Dim resp = client.SendAsync(msg).Result
Dim strLastMod As String = resp.Content.Headers.LastModified.ToString
MsgBox("Last mod as string date" & vbCrLf & strLastMod)
Dim lastMod As DateTime = strLastMod
MsgBox(lastMod)
End Sub
Private Sub GetURLdate1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
TextBox1.Text =
"https://stackoverflow.com/questions/70825821/how-do-i-get-last-modified-date-of-website"
End Sub
So, I used THIS web page for the url.
When I run this form - click on button, I see this: